Rock-drill



(No Model.)

J. E. SMITH.

ROCK DRILL.

N0. 520,619. Patented May 29, 1894.

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'ruz NATIONAL umossupmne ccunm' STATES JOSEPH l-I. SMITH, OF PLYMOUTH,OHIO.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 520,619, dated May 29,1894.

Application filed September 14., 1 e93. semi No. 485,502. (No model.)

To all whom it may concern:

Be it known that I, J OSEPH H. SMITH, a citizen of the United States,residingat Plymouth, in the county of Richland and State of Ohio, haveinvented a new and useful Rock-Drill, of which the following is aspecification.

My invention relates to improvements in that class of drills employedfor drilling holes in rock or stone for the reception of blasts or othermeans for forcibly splitting the rock or stone along the line of theholes.

The objects of my invention are to produce a drill designed for thispurpose, the same being so constructed or formed as to obviate stickingand which shall produce such character of holes as will cause thesplitting power or force to exert itself in line with the holes therebycausing a continuous fracture in the desired direction.

Various other objects and advantages of the invention will appear in thefollowing description and the novel features thereof will beparticularly pointed out in the claims.

Referring to the drawings:Figure 1 is a perspective view of a drillconstructed in accordance with my invention. Fig. 2 is a verticallongitudinal sectional View of the same. Fig. 3 is a transversesectional view through the lower end of the drill. Fig. 4 is a bottomplan view of the drill. Fig. 5 is a modified construction of drill inside elevation. Fig. 6 shows plans of holes produced by my drill. Fig. 7is a similar view of other holes usually produced.

The drill comprises a shank 1 which may be round or rectangular incross-section, as preferred. The shank terminates at its lower end in awidened head 2, which when viewed in cross-section is somewhatelliptical. In other words, the said head comprises opposite convexcdexterior or side -faces. The production of this head forms oppositeshoulders at the side of the shank, and through these shoulders verticalopenings or clearance openings 3 are formed, the same being separated byan intermediate integral solid Vertical transverse wall 4:, whose loweredge is reduced at each sideto form the cuttingedge 5. The lower edgesof the convexed sides 3 are at their inner faces beveled so as to formcutting-edges 6, and by this beveling at the sides of the partition 4and the sidewalls it will be seen that I provide a continuouscutting-edge and also flared entrances to the lower ends of theclearance-openings 3, so that in operation, the tendency is to cause thedust, chips, 850., to be directed from the wall of the opening towardthe centers of the clearance-holes.

I preferably make the drills double-pointed, that is, form oppositepoints 7 at each side of the two clearance-openings. Such constructionis especially designed for operating upon extremely hard rock or stone,but in the ordinary stone I may omit the double-points and form thedrill as shown in Fig. 5, that is, incline the cutting-edge from theopposite ends to the center cutter 5.

In operating my drill, round holes are not first drilled as is usualwith other drills, but my drill is placed or centered in the line inwhich direction it is desired to break the rock, after which said drillis reciprocated by hand or machine and a hole formed of the shape whichI have illustrated in Fig. 6, wherein it will be seen that said holesare in the shape of narrow ellipses, the opposite ends being sharp andwell defined. By the production of these holes the splitting effect orforce is so disposed as to cause the rock or stone to be fractureddirectly in a continuous line, as indicated in Fig. 6. In Fig. 7 I haveillustrated a hole commonly formed, and wherein it will be seen thatthefracture is not continuous, but the force being diffused in variousdirections various fractures are sure to result and thus cause anunsatisfactory result. The splitting may be secured by blasting orthrough the ordinary hand-wedge operation. Continuing the operation ofthe tool as before stated, it will be observed that the chips and dustare carefully taken from the wall of the opening and are directed towardthe centers of the clearance-openings or channels up through which theypass, so that as will be obvious, no packing of the dust or powderedstone can occur upon the walls of the opening or at the angles at thebottom, which would tend to obstruct the ready movement of the tool.Attention is called to the fact that the clearance-openings or holes arewholly within the wall or the head of the tool, so that the said wallremains unbroken and smooth and all portions of the wall of the opening.that the tool forms are operated upon by the cutting-edge of the tool.

I do not limit my invention to the precise details of constructionherein shown and described, but hold that I may vary the same to anydegree and extent within the knowledge of the skilled mechanic.

Having described my invention, what I claim is 1. The herein describedrock drill, the same having at its lower end a head having externalcontinuously curved sides approximating in cross-section an ellipse,clearanceopenings located within the head at each side of the centerthereof and producing an intermediate partition having a lowercuttingedge, and a cutting-edge located at the lower end of thesurrounding wall, substantially as

